Some X-ray examining procedures can involve more than routine discomfort and hazards to a diagnostic patient. In patients with coronary artery disease, oblique views of the right and left anterior ventricle are considered optimal for assessment of regional wall motion. With equipment previously used, the patient was strapped to a cradle and a radiological examination on one plane was made and then the patient was tilted on the cradle to provide for examination in the second plane. Such examinations are not desirable because the procedure of tilting the patient to take biplanar views can be traumatic. In addition to the patient's motional discomfort, the time required for a series of biplanar X-ray exposures through the organ examined and the accumulation of X-ray dosage should be minimized. Also the amount of radiopaque or radioisotopic injected material must be minimized while maximizing the number of exposures over a wide range of angles. For example, in radiological examination of the heart a radiopaque liquid, toxic in large concentrations, is injected through a suitable arterial system for each X-ray exposure which must be made quickly. The injection toxicity, discomfort, and elapsed time can be reduced by one half by making two X-ray exposures simultaneously or in rapid sequence in two planes through the subject. Apparatus for taking two biplanar X-ray exposures of a subject is shown in U.S. Pat. No. 3,459,885 to Andersson and U.S. Pat. No. 3,659,099 to Bertheau. While the apparatus of these patents simultaneous biplanar exposures of a subject at the intersection of the two axes, the two axes are fixed at a right angle to each other. Two biplanar exposures at right angles through a subject are not always at the best or the necessary angle for useful examination of the subject. If the optimum angle or plane for one exposure is selected, the relatively fixed angle of the second exposure may be useless. Moreover, it is often desirable to repeat the exposure in one plane while changing the second exposure plane. Accordingly, one object of the present invention is to provide apparatus for biplanar radiological examination on two axes through a common subject which permits adjustment of one axis relative to the other.
Also, although it is possible to make fixed angle biplanar exposures with the apparatus of the Andersson and Bertheau patents, both patentees recognize the problem of ready access to the patient through the two sets of X-ray equipment. It is a further object of the present invention to permit free access to the patient in biplane X-ray apparatus.